Effect of Acidic Environment on the Push-out Bond Strength of BiodentineTM

Introduction: An apical sealing material may be exposed to an inflamed environment with low pH levels. The change in physical and chemical properties of mineral trioxide aggregate has been well-documented in the presence of low pH. However, on literature search there is no documentation of the effect of low pH on BiodentineTM. Aim: To compare the effects of various levels of acidic pH on the push-out bond strength of BiodentineTM. Materials and methods: Forty root dentin slices from single rooted human teeth were sectioned horizontally. The canal lumens were instrumented to obtain a standardized diameter of 1.3 mm and filled with BiodentineTM. The specimens were then randomly divided into four groups (n = 10) and wrapped in pieces of gauze soaked in phosphate buffer saline solution (pH = 7.4) and butyric acid buffered at pH values of 4.4, 5.4 and 6.4 respectively. They were incubated at 37°C for 4 days. Push-out test were then carried out using universal testing machine. The data was analyzed using one-way analysis of variance (ANOVA) technique with Tukey’s correction for multiple group comparisons. Results: Data was subjected to one-way ANOVA using Tukey’s post hoc test. Group I (control, pH = 7.4) showed greatest bond strength of 19.5 ± 0.9 MPa. The least push-out bond strength of 11.7 ± 0.5 MPa was observed in Group IV where the specimens were soaked at pH 4.4. A p-value less than 0.05 were considered to be statistically significant. Conclusion: The force needed to displace Biodentine was significantly lower in samples stored at lower pH values.